BAKERSFIELD, Calif. — A mysterious malady that has been killing honeybees en masse for several years appears to have expanded drastically in the last year, commercial beekeepers say, wiping out 40 percent or even 50 percent of the hives needed to pollinate many of the nation’s fruits and vegetables.

A conclusive explanation so far has escaped scientists studying the ailment, colony collapse disorder, since it first surfaced around 2005. But beekeepers and some researchers say there is growing evidence that a powerful new class of pesticides known as neonicotinoids, incorporated into the plants themselves, could be an important factor.

The pesticide industry disputes that. But its representatives also say they are open to further studies to clarify what, if anything, is happening.

“They looked so healthy last spring,” said Bill Dahle, 50, who owns Big Sky Honey in Fairview, Mont. “We were so proud of them. Then, about the first of September, they started to fall on their face, to die like crazy. We’ve been doing this 30 years, and we’ve never experienced this kind of loss before.”

Beekeepers with Big Sky Honey worked with hives used to pollinate almond groves in Bakersfield, Calif.Photo Credit: Jim Wilson/The New York Times

In a show of concern, the Environmental Protection Agency recently sent its acting assistant administrator for chemical safety and two top chemical experts here, to the San Joaquin Valley of California, for discussions.

In the valley, where 1.6 million hives of bees just finished pollinating an endless expanse of almond groves, commercial beekeepers who only recently were losing a third of their bees to the disorder say the past year has brought far greater losses.

The federal Agriculture Department is to issue its own assessment in May. But in an interview, the research leader at its Beltsville, Md., bee research laboratory, Jeff Pettis, said he was confident that the death rate would be “much higher than it’s ever been.”

Following a now-familiar pattern, bee deaths rose swiftly last autumn and dwindled as operators moved colonies to faraway farms for the pollination season. Beekeepers say the latest string of deaths has dealt them a heavy blow.

Bret Adee, who is an owner, with his father and brother, of Adee Honey Farms of South Dakota, the nation’s largest beekeeper, described mounting losses.

“We lost 42 percent over the winter. But by the time we came around to pollinate almonds, it was a 55 percent loss,” he said in an interview here this week.

“They looked beautiful in October,” Mr. Adee said, “and in December, they started falling apart, when it got cold.”

Mr. Dahle said he had planned to bring 13,000 beehives from Montana — 31 tractor-trailers full — to work the California almond groves. But by the start of pollination last month, only 3,000 healthy hives remained.

Annual bee losses of 5 percent to 10 percent once were the norm for beekeepers. But after colony collapse disorder surfaced around 2005, the losses approached one-third of all bees, despite beekeepers’ best efforts to ensure their health.

Nor is the impact limited to beekeepers. The Agriculture Department says a quarter of the American diet, from apples to cherries to watermelons to onions, depends on pollination by honeybees. Fewer bees means smaller harvests and higher food prices.

Almonds are a bellwether. Eighty percent of the nation’s almonds grow here, and 80 percent of those are exported, a multibillion-dollar crop crucial to California agriculture. Pollinating up to 800,000 acres, with at least two hives per acre, takes as many as two-thirds of all commercial hives.

This past winter’s die-off sent growers scrambling for enough hives to guarantee a harvest. Chris Moore, a beekeeper in Kountze, Tex., said he had planned to skip the groves after sickness killed 40 percent of his bees and left survivors weakened.

“But California was short, and I got a call in the middle of February that they were desperate for just about anything,” he said. So he sent two truckloads of hives that he normally would not have put to work.

Bee shortages pushed the cost to farmers of renting bees to $200 per hive at times, 20 percent above normal. That, too, may translate into higher prices for food.

Bill Dahle, the owner, described a startling loss of honeybees last year.Photo Credit: Jim Wilson/The New York Times

Precisely why last year’s deaths were so great is unclear. Some blame drought in the Midwest, though Mr. Dahle lost nearly 80 percent of his bees despite excellent summer conditions. Others cite bee mites that have become increasingly resistant to pesticides. Still others blame viruses.

But many beekeepers suspect the biggest culprit is the growing soup of pesticides, fungicides and herbicides that are used to control pests.

While each substance has been certified, there has been less study of their combined effects. Nor, many critics say, have scientists sufficiently studied the impact of neonicotinoids, the nicotine-derived pesticide that European regulators implicate in bee deaths.

The explosive growth of neonicotinoids since 2005 has roughly tracked rising bee deaths.

Neonics, as farmers call them, are applied in smaller doses than older pesticides. They are systemic pesticides, often embedded in seeds so that the plant itself carries the chemical that kills insects that feed on it.

Older pesticides could kill bees and other beneficial insects. But while they quickly degraded — often in a matter of days — neonicotinoids persist for weeks and even months. Beekeepers worry that bees carry a summer’s worth of contaminated pollen to hives, where ensuing generations dine on a steady dose of pesticide that, eaten once or twice, might not be dangerous.

“Soybean fields or canola fields or sunflower fields, they all have this systemic insecticide,” Mr. Adee said. “If you have one shot of whiskey on Thanksgiving and one on the Fourth of July, it’s not going to make any difference. But if you have whiskey every night, 365 days a year, your liver’s gone. It’s the same thing.”

Research to date on neonicotinoids “supports the notion that the products are safe and are not contributing in any measurable way to pollinator health concerns,” the president of CropLife America, Jay Vroom, said Wednesday. The group represents more than 90 pesticide producers.

He said the group nevertheless supported further research. “We stand with science and will let science take the regulation of our products in whatever direction science will guide it,” Mr. Vroom said.

A coalition of beekeepers and environmental and consumer groups sued the E.P.A. last week, saying it exceeded its authority by conditionally approving some neonicotinoids. The agency has begun an accelerated review of their impact on bees and other wildlife.

The European Union has proposed to ban their use on crops frequented by bees. Some researchers have concluded that neonicotinoids caused extensive die-offs in Germany and France.

Neonicotinoids are hardly the beekeepers’ only concern. Herbicide use has grown as farmers have adopted crop varieties, from corn to sunflowers, that are genetically modified to survive spraying with weedkillers. Experts say some fungicides have been laced with regulators that keep insects from maturing, a problem some beekeepers have reported.

Bees on a honeycomb pulled from a hive at Big Sky Honey.Photo Credit: Jim Wilson/The New York Times

Eric Mussen, an apiculturist at the University of California, Davis, said analysts had documented about 150 chemical residues in pollen and wax gathered from beehives.

“Where do you start?” Dr. Mussen said. “When you have all these chemicals at a sublethal level, how do they react with each other? What are the consequences?”

Experts say nobody knows. But Mr. Adee, who said he had long scorned environmentalists’ hand-wringing about such issues, said he was starting to wonder whether they had a point.

Of the “environmentalist” label, Mr. Adee said: “I would have been insulted if you had called me that a few years ago. But what you would have called extreme — a light comes on, and you think, ‘These guys really have something. Maybe they were just ahead of the bell curve.’”

If it were a novel, people would criticize the plot for being too far-fetched – thriving colonies disappear overnight without leaving a trace, the bodies of the victims are never found. Only in this case, it’s not fiction: It’s what’s happening to fully a third of commercial beehives, over a million colonies every year. Seemingly healthy communities fly off never to return. The queen bee and mother of the hive is abandoned to starve and die.

Thousands of scientific sleuths have been on this case for the last 15 years trying to determine why our honey bees are disappearing in such alarming numbers. “This is the biggest general threat to our food supply,” according to Kevin Hackett, the national program leader for the U.S. Department of Agriculture’s bee and pollination program.

Until recently, the evidence was inconclusive on the cause of the mysterious “colony collapse disorder” (CCD) that threatens the future of beekeeping worldwide. But three new studies point an accusing finger at a culprit that many have suspected all along, a class of pesticides known as neonicotinoids.

In the U.S. alone, these pesticides, produced primarily by the German chemical giant Bayer and known as “neonics” for short, coat a massive 142 million acres of corn, wheat, soy and cotton seeds. They are also a common ingredient in home gardening products.

Research published last month in the prestigious journal Science shows that neonics are absorbed by the plants’ vascular system and contaminate the pollen and nectar that bees encounter on their rounds. They are a nerve poison that disorient their insect victims and appear to damage the homing ability of bees, which may help to account for their mysterious failure to make it back to the hive.

Another study published in the American Chemical Society’s Environmental Science and Technology journal implicated neonic-containing dust released into the air at planting time with “lethal effects compatible with colony losses phenomena observed by beekeepers.”

Purdue University entomologists observed bees at infected hives exhibiting tremors, uncoordinated movement and convulsions, all signs of acute insecticide poisoning. And yet another study conducted by scientists at the Harvard School of Public Health actually re-created colony collapse disorder in several honeybee hives simply by administering small doses of a popular neonic, imidacloprid.

But scientists believe that exposure to toxic pesticides is only one factor that has led to the decline of honey bees in recent years. The destruction and fragmentation of bee habitats, as a result of land development and the spread of monoculture agriculture, deprives pollinators of their diverse natural food supply. This has already led to the extinction of a number of wild bee species. The planting of genetically modified organism (GMO) crops – some of which now contain toxic insecticides within their genetic structure – may also be responsible for poisoning bees and weakening their immune systems.

Every spring millions of bee colonies are trucked to the Central Valley of California and other agricultural areas to replace the wild pollinators, which have all but disappeared in many parts of the country. These bees are routinely fed high-fructose corn syrup instead of their own nutritious honey. And in an effort to boost productivity, the queens are now artificially inseminated, which has led to a disturbing decline in bee genetic diversity. Bees are also dusted with chemical poisons to control mites and other pathogens that have flourished in the overcrowded commercial colonies.

In 1923, Rudolph Steiner, the German founder of biodynamic agriculture, a precursor of the modern organic movement, predicted that within a hundred years artificial industrial techniques used to breed honey bees would lead to the species’ collapse. His prophecy was right on target!

Honey bees have been likened to the canaries in the coal mine. Their vanishing is nature’s way of telling us that conditions have deteriorated in the world around us. Bees won’t survive for long if we don’t change our commercial breeding practices and remove deadly toxins from their environment. A massive pollinator die-off would imperil world food supplies and devastate ecosystems that depend on them. The loss of these creatures might rival climate change in its impact on life on earth.

Still, this is a disaster that does not need to happen. Germany and France have already banned pesticides that have been implicated in the deaths of bees. There is still time to save the bees by working with nature rather than against it, according to environmentalist and author Bill McKibben:

“Past a certain point, we can’t make nature conform to our industrial model. The collapse of beehives is a warning – and the cleverness of a few beekeepers in figuring out how to work with bees not as masters but as partners offers a clear-eyed kind of hope for many of our ecological dilemmas.”

[PHOTO: A bumblebee sits on a rhododendron bloom on a sunny spring day in Dortmund, Germany, March 28, 2012. REUTERS/Ina Fassbender]

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Why “Urban” Beekeeping?

We at HoneyLove believe that the city is the last refuge of the honeybee. Our home gardens are generally free of pesticides, and in cities like Los Angeles, there is year-round availability of pollen and nectar for the honeybees!

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Become a member of HoneyLove and learn to be an urban beekeeper!

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